1
|
Curcio CA. Soft Drusen in Age-Related Macular Degeneration: Biology and Targeting Via the Oil Spill Strategies. Invest Ophthalmol Vis Sci 2018; 59:AMD160-AMD181. [PMID: 30357336 PMCID: PMC6733535 DOI: 10.1167/iovs.18-24882] [Citation(s) in RCA: 184] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
AMD is a major cause of legal blindness in older adults approachable through multidisciplinary research involving human tissues and patients. AMD is a vascular-metabolic-inflammatory disease, in which two sets of extracellular deposits, soft drusen/basal linear deposit (BLinD) and subretinal drusenoid deposit (SDD), confer risk for end-stages of atrophy and neovascularization. Understanding how deposits form can lead to insights for new preventions and therapy. The topographic correspondence of BLinD and SDD with cones and rods, respectively, suggest newly realized exchange pathways among outer retinal cells and across Bruch's membrane and the subretinal space, in service of highly evolved, eye-specific physiology. This review focuses on soft drusen/BLinD, summarizing evidence that a major ultrastructural component is large apolipoprotein B,E-containing, cholesterol-rich lipoproteins secreted by the retinal pigment epithelium (RPE) that offload unneeded lipids of dietary and outer segment origin to create an atherosclerosis-like progression in the subRPE-basal lamina space. Clinical observations and an RPE cell culture system combine to suggest that soft drusen/BLinD form when secretions of functional RPE back up in the subRPE-basal lamina space by impaired egress across aged Bruch's membrane-choriocapillary endothelium. The soft drusen lifecycle includes growth, anterior migration of RPE atop drusen, then collapse, and atrophy. Proof-of-concept studies in humans and animal models suggest that targeting the “Oil Spill in Bruch's membrane” offers promise of treating a process in early AMD that underlies progression to both end-stages. A companion article addresses the antecedents of soft drusen within the biology of the macula.
Collapse
Affiliation(s)
- Christine A Curcio
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| |
Collapse
|
2
|
Ketelhuth DFJ, Rios FJO, Wang Y, Liu H, Johansson ME, Fredrikson GN, Hedin U, Gidlund M, Nilsson J, Hansson GK, Yan ZQ. Identification of a danger-associated peptide from apolipoprotein B100 (ApoBDS-1) that triggers innate proatherogenic responses. Circulation 2011; 124:2433-43, 1-7. [PMID: 22064596 DOI: 10.1161/circulationaha.111.051599] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND Subendothelial deposited low-density lipoprotein particles are a known inflammatory factor in atherosclerosis. However, the causal components derived from low-density lipoprotein are still poorly defined. Apolipoprotein B100 (ApoB100) is the unexchangeable protein component of low-density lipoprotein, and the progression of atherosclerosis is associated with immune responses to ApoB100-derived peptides. In this study, we analyzed the proinflammatory activity of ApoB100 peptides in atherosclerosis. METHODS AND RESULTS By screening a peptide library of ApoB100, we identified a distinct native peptide referred to as ApoB100 danger-associated signal 1 (ApoBDS-1), which shows sequence-specific bioactivity in stimulation of interleukin-8, CCL2, and interleukin-6. ApoBDS-1 activates mitogen-activated protein kinase and calcium signaling, thereby effecting the expression of interleukin-8 in innate immune cells. Ex vivo stimulation of carotid plaques with ApoBDS-1 enhances interleukin-8 and prostaglandin E₂ release. Furthermore, we demonstrated that ApoBDS-1-positive peptide fragments are present in atherosclerotic lesions using immunoassays and that low-molecular-weight fractions isolated from plaque show ApoBDS-1 activity inducing interleukin-8 production. CONCLUSIONS Our data show that ApoBDS-1 is a previously unrecognized peptide with robust proinflammatory activity, contributing to the disease-promoting effects of low-density lipoprotein in the pathogenesis of atherosclerosis.
Collapse
Affiliation(s)
- Daniel F J Ketelhuth
- Center for Molecular Medicine, Department of Medicine, Karolinska Institute, Stockholm, Sweden
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
3
|
Zou MH, Li H, He C, Lin M, Lyons TJ, Xie Z. Tyrosine nitration of prostacyclin synthase is associated with enhanced retinal cell apoptosis in diabetes. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 179:2835-44. [PMID: 22015457 DOI: 10.1016/j.ajpath.2011.08.041] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 08/08/2011] [Accepted: 08/29/2011] [Indexed: 02/07/2023]
Abstract
The risk of diabetic retinopathy is associated with the presence of both oxidative stress and toxic eicosanoids. Whether oxidative stress actually causes diabetic retinopathy via the generation of toxic eicosanoids, however, remains unknown. The aim of the present study was to determine whether tyrosine nitration of prostacyclin synthase (PGIS) contributes to retinal cell death in vitro and in vivo. Exposure of human retinal pericytes to heavily oxidized and glycated LDL (HOG-LDL), but not native forms of LDL (N-LDL), for 24 hours significantly increased pericyte apoptosis, accompanied by increased tyrosine nitration of PGIS and decreased PGIS activity. Inhibition of the thromboxane receptor or cyclooxygenase-2 dramatically attenuated HOG-LDL-induced apoptosis without restoring PGIS activity. Administration of superoxide dismutase (to scavenge superoxide anions) or L-N(G)-nitroarginine methyl ester (L-NAME, a nonselective nitric oxide synthase inhibitor) restored PGIS activity and attenuated pericyte apoptosis. In Akita mouse retinas, diabetes increased intraretinal levels of oxidized LDL and glycated LDL, induced PGIS nitration, enhanced apoptotic cell death, and impaired blood-retinal barrier function. Chronic administration of tempol, a superoxide scavenger, reduced intraretinal oxidized LDL and glycated LDL levels, PGIS nitration, and retina cell apoptosis, thereby preserving the integrity of blood-retinal barriers. In conclusion, oxidized LDL-mediated PGIS nitration and associated thromboxane receptor stimulation might be important in the initiation and progression of diabetic retinopathy.
Collapse
Affiliation(s)
- Ming-Hui Zou
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
| | | | | | | | | | | |
Collapse
|
4
|
Plihtari R, Hurt-Camejo E, Oörni K, Kovanen PT. Proteolysis sensitizes LDL particles to phospholipolysis by secretory phospholipase A2 group V and secretory sphingomyelinase. J Lipid Res 2010; 51:1801-9. [PMID: 20124257 DOI: 10.1194/jlr.m003103] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
LDL particles that enter the arterial intima become exposed to proteolytic and lipolytic modifications. The extracellular hydrolases potentially involved in LDL modification include proteolytic enzymes, such as chymase, cathepsin S, and plasmin, and phospholipolytic enzymes, such as secretory phospholipases A2 (sPLA2-IIa and sPLA2-V) and secretory acid sphingomyelinase (sSMase). Here, LDL was first proteolyzed and then subjected to lipolysis, after which the effects of combined proteolysis and lipolysis on LDL fusion and on binding to human aortic proteoglycans (PG) were studied. Chymase and cathepsin S led to more extensive proteolysis and release of peptide fragments from LDL than did plasmin. sPLA2-IIa was not able to hydrolyze unmodified LDL, and even preproteolysis of LDL particles failed to enhance lipolysis by this enzyme. However, preproteolysis with chymase and cathepsin S accelerated lipolysis by sPLA2-V and sSMase, which resulted in enhanced fusion and proteoglycan binding of the preproteolyzed LDL particles. Taken together, the results revealed that proteolysis sensitizes the LDL particles to hydrolysis by sPLA2-V and sSMase. By promoting fusion and binding of LDL to human aortic proteoglycans, the combination of proteolysis and phospholipolysis of LDL particles potentially enhances extracellular accumulation of LDL-derived lipids during atherogenesis.
Collapse
|
5
|
Lee HS, Kruth HS. Accumulation of cholesterol in the lesions of focal segmental glomerulosclerosis. Nephrology (Carlton) 2008; 8:224-3. [PMID: 15012708 DOI: 10.1046/j.1440-1797.2003.00160.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Intraglomerular deposition of low-density lipoprotein (LDL) and oxidized LDL has been described in various human glomerular diseases. Yet it is not clear whether esterified cholesterol (EC) and unesterified cholesterol (UC) carried in LDL are mobilized from deposited LDL particles or accumulate in the diseased human glomeruli, particularly in the segmentally sclerotic lesions. To address this issue, frozen sections of renal biopsies were first immunostained to localize apolipoprotein B (apo B) and then oil red O (ORO) stained to colocalize neutral lipids. By using 124 ORO-positive biopsies and nine ORO-negative ones, UC was visualized directly with filipin staining, and EC was visualized after its enzymatic hydrolysis and staining with filipin. Seventy-seven biopsies (58%) showed filipin staining of accumulated EC and/or UC in the glomeruli. Of these, 11 showed heavy filipin staining for both EC and UC in the segmentally sclerotic lesions. In a group with UC deposits in the sclerotic segments, the percentage of the glomeruli affected by sclerosis and the intensity of filipin fluorescence for UC were significantly higher than biopsies with only mesangial UC deposits. Most filipin-positive biopsies showed apo B staining mainly in the mesangium. Yet in the sclerotic segments, apo B staining was rarely noted. Accumulated apo B-stained lipoprotein was not coincident with ORO-stained lipid in the diseased glomeruli. These results suggest that both EC and UC accumulate in the sclerotic glomerular segments as the glomerular lesions are advanced, and that these EC and UC appear to be derived from altered LDL with progressive loss of apo B.
Collapse
Affiliation(s)
- Hyun Soon Lee
- Department of Pathology, Seoul National University College of Medicine, Seoul, Korea.
| | | |
Collapse
|
6
|
Linke M, Gordon RE, Brillard M, Lecaille F, Lalmanach G, Brömme D. Degradation of apolipoprotein B-100 by lysosomal cysteine cathepsins. Biol Chem 2006; 387:1295-303. [PMID: 16972799 DOI: 10.1515/bc.2006.160] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Although the degradation of cellular or endocytosed proteins comprises the normal function of lysosomal proteinases, these enzymes were also detected extracellularly during diseases such as atherosclerosis. Since lysosomal cysteine cathepsins were demonstrated to transform native LDL particles into a proatherogenic type, the following study was undertaken to characterize the modification of LDL particles and the degradation of apolipoprotein B-100 in more detail. LDL was incubated with cathepsins B, F, K, L, S, and V at pH 5.5 and under physiological conditions (pH 7.4) for 2 h to mimic conditions of limited proteolysis. Gel electrophoretic analysis of the degradation products revealed that cathepsin-mediated proteolysis of apolipoprotein B-100 is a fast process carried out by all enzymes at pH 5.5, and by cathepsin S also at pH 7.4. Electron microscopic analysis showed that cathepsin-mediated degradation of apolipoprotein B-100 rendered LDL particles fusion-competent compared to controls. N-Terminal sequencing of cathepsin cleavage fragments from apolipoprotein B-100 revealed an abundance of enzyme-specific cleavage sites located in almost all structurally and functionally essential regions. Since the cleavage sites superimpose well with results from substrate specificity studies, they might be useful for the development of cathepsin-specific inhibitors and substrates.
Collapse
Affiliation(s)
- Martin Linke
- Department of Dentistry and UBC Center for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia V6T 1Z3, Canada
| | | | | | | | | | | |
Collapse
|
7
|
Bobryshev YV. Calcification of elastic fibers in human atherosclerotic plaque. Atherosclerosis 2005; 180:293-303. [PMID: 15910855 DOI: 10.1016/j.atherosclerosis.2005.01.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2004] [Accepted: 12/08/2004] [Indexed: 10/25/2022]
Abstract
The present study was undertaken to systematically investigate whether calcification of elastic fibers occurs in human atherosclerotic plaques. Fourteen carotid artery segments obtained by endarterectomy were examined by a combination of electron microscopy and cytochemistry. The analysis demonstrated that calcification of elastic fibers occurred in all 14 specimens. Two distinct types of calcification of elastic fibers were identified. In type I calcification, elastin itself was observed to undergo calcification and no visible structural alterations preceded the calcification. In type II of calcification, structural alteration of elastin preceded calcification of elastic fibers and included vacuolization of elastin accompanied by the accumulation of neutral lipids and unesterified cholesterol within altered elastic fibers. In type II calcification, calcified deposits were found to form in an association with unesterified cholesterol. Type II calcification was widespread throughout the plaque matrix while type I calcification occurred only in the deep portions of plaques.
Collapse
Affiliation(s)
- Yuri V Bobryshev
- Surgical Professorial Unit, Level 5, DeLacy Building, St. Vincent's Hospital Sydney, University of New South Wales, Darlinghurst NSW 2010, Australia.
| |
Collapse
|
8
|
Oörni K, Sneck M, Brömme D, Pentikäinen MO, Lindstedt KA, Mäyränpää M, Aitio H, Kovanen PT. Cysteine protease cathepsin F is expressed in human atherosclerotic lesions, is secreted by cultured macrophages, and modifies low density lipoprotein particles in vitro. J Biol Chem 2004; 279:34776-84. [PMID: 15184381 DOI: 10.1074/jbc.m310814200] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During atherogenesis, low density lipoprotein (LDL) particles in the arterial intima become modified and fuse to form extracellular lipid droplets. Proteolytic modification of apolipoprotein (apo) B-100 may be one mechanism of droplet formation from LDL. Here we studied whether the newly described acid protease cathepsin F can generate LDL-derived lipid droplets in vitro. Treatment of LDL particles with human recombinant cathepsin F led to extensive degradation of apoB-100, which, as determined by rate zonal flotation, electron microscopy, and NMR spectroscopy, triggered both aggregation and fusion of the LDL particles. Two other acid cysteine proteases, cathepsins S and K, which have been shown to be present in the arterial intima, were also capable of degrading apoB-100, albeit less efficiently. Cathepsin F treatment resulted also in enhanced retention of LDL to human arterial proteoglycans in vitro. Cultured monocyte-derived macrophages were found to secrete active cathepsin F. In addition, similarly with cathepsins S and K, cathepsin F was found to be localized mainly within the macrophage-rich areas of the human coronary atherosclerotic plaques. These results suggest that proteolytic modification of LDL by cathepsin F may be one mechanism leading to the extracellular accumulation of LDL-derived lipid droplets within the proteoglycan-rich extracellular matrix of the arterial intima during atherogenesis.
Collapse
Affiliation(s)
- Katariina Oörni
- Wihuri Research Institute, Kalliolinnantie 4, FIN-00140 Helsinki, Finland.
| | | | | | | | | | | | | | | |
Collapse
|
9
|
Cusick M, Chew EY, Chan CC, Kruth HS, Murphy RP, Ferris FL. Histopathology and regression of retinal hard exudates in diabetic retinopathy after reduction of elevated serum lipid levels. Ophthalmology 2003; 110:2126-33. [PMID: 14597519 DOI: 10.1016/j.ophtha.2003.01.001] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
PURPOSE To describe a regression of retinal hard exudates in 2 patients with diabetic maculopathy, and to report immunohistologic findings reflecting lipid deposition in the retina. DESIGN Two interventional case reports. METHODS Two patients with exudative diabetic maculopathy were treated to normalize serum lipids. Histologic examination and immunohistochemistry of each patient's eyes were performed to assess the localization of apolipoprotein B and cholesteryl ester, both of which are principal components of low-density lipoprotein. RESULTS Both patients showed a dramatic regression of retinal hard exudates after correction of dyslipidemia. Histopathology revealed diffuse lipids and cholesteryl ester in the retina. Apolipoprotein B and macrophages were colocalized in the perivascular space. CONCLUSIONS The regression of hard exudates was most likely due to the aggressive lipid lowering in both patients. The novel histopathologic findings of hard exudate and diabetic maculopathy are similar to the pathologic changes observed in larger atherosclerotic lesions, except that they occur in the intraretinal perivascular space.
Collapse
Affiliation(s)
- Michael Cusick
- Division of Epidemiology and Clinical Research, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | | | | | | | |
Collapse
|
10
|
Kruth HS, Huang W, Ishii I, Zhang WY. Macrophage foam cell formation with native low density lipoprotein. J Biol Chem 2002; 277:34573-80. [PMID: 12118008 DOI: 10.1074/jbc.m205059200] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
This investigation has elucidated a mechanism for development of macrophage foam cells when macrophages are incubated with native low density lipoprotein (LDL). LDL is believed to be the main source of cholesterol that accumulates in monocyte-derived macrophages within atherosclerotic plaques, but native LDL has not previously been shown to cause substantial cholesterol accumulation when incubated with macrophages. We have found that activation of human monocyte-derived macrophages with phorbol 12-myristate 13-acetate (PMA) stimulates LDL uptake and degradation and acyl-CoA:cholesterol acyltransferase-mediated esterification of LDL-derived cholesterol, resulting in massive macrophage cholesterol accumulation that could exceed 400 nmol/mg of cell protein. Cholesterol accumulation showed a biphasic linear LDL concentration dependence with LDL levels as high as 4 mg/ml, similar to LDL levels in artery intima. Protein kinase C mediated the PMA-stimulated macrophage uptake of LDL because the protein kinase C inhibitors, Gö6983 and GF109203X, inhibited cholesterol accumulation. LDL receptors did not mediate macrophage cholesterol accumulation because accumulation occurred with reductively methylated LDL and in the presence of an anti-LDL receptor-blocking monoclonal antibody. LDL-induced cholesterol accumulation was not inhibited by antioxidants, was not accompanied by increased LDL binding to macrophages, did not depend on the apoB component of LDL, and was not down-regulated by prior cholesterol enrichment of macrophages. We have shown that the mechanism of LDL uptake by macrophages was PMA-stimulated endocytosis of LDL taken up as part of the bulk phase fluid (i.e. fluid phase endocytosis). The amount of LDL taken up with the bulk phase fluid was measured with [(3)H]sucrose and accounted for a minimum of 83% of the LDL cholesterol delivery and accumulation in PMA-activated macrophages. This novel mechanism of macrophage cholesterol accumulation shows that modification of LDL is not necessary for foam cell formation to occur. In addition, the findings direct attention to macrophage fluid phase endocytosis as a relevant pathway to target for modulating macrophage cholesterol accumulation in atherosclerosis.
Collapse
Affiliation(s)
- Howard S Kruth
- Section of Experimental Atherosclerosis, NHLBI/National Institutes of Health, Bldg. 10 Rm. 5N-113, 10 Center Drive, MSC 1422, Bethesda, MD 20892, USA.
| | | | | | | |
Collapse
|
11
|
Aggregation, fusion, and vesicle formation of modified low density lipoprotein particles: molecular mechanisms and effects on matrix interactions. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)31964-7] [Citation(s) in RCA: 180] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
12
|
Bobryshev YV, Lord RS. Accumulation of co-localised unesterified cholesterol and neutral lipids within vacuolised elastin fibres in athero-prone areas of the human aorta. Atherosclerosis 1999; 142:121-31. [PMID: 9920513 DOI: 10.1016/s0021-9150(98)00202-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To investigate whether there are alterations of elastin fibres in the arterial intima at the pre-atherosclerotic stage, grossly normal areas of human thoracic aorta were taken soon after death from 13 healthy trauma victims whose ages ranged from 16 to 40 years. Two areas were compared: atherosclerosis-prone (AP) areas localised to the dorsal aspect of the aorta along the rows of intercostal branch origins, and atherosclerosis-resistant (AR) areas from the ventral aorta. Electron microscopic analysis combined with cytochemical staining was applied. Unesterified cholesterol was identified using the filipin-staining technique while neutral lipids were visualised by the OTO-technique. Intimal features were studied by combining the filipin-staining and the OTO-technique. Electron microscopical examination showed that in both AR and AP areas, some elastin fibres in the intima were vacuolised. Unesterified cholesterol was found to be predominantly localised in the musculoelastic layer, in particular, inside the vacuolised elastin fibres. This localisation was seen in all 13 AP areas studied in contrast to the AR areas where it was observed in only four of 13 aortas studied (P < 0.0005, chi2-test). Accumulation of neutral lipids inside vacuolised elastin fibres was found in five out of 13 AP areas but was not observed in any of the AR areas (P=0.01, chi2). A combination of the filipin-staining and OTO-techniques showed that some deposits of neutral lipids and unesterified cholesterol within vacuolised elastin fibres were independently located from each other, but more frequently, neutral lipids were co-located with unesterified cholesterol. The present observations indicate a difference between AP and AR intimal areas which, in particular, relates to the structure of elastin fibres in the musculoelastic layer. The observations suggest that alterations of the extracellular matrix are involved in the trapping and retention of cholesterol and neutral lipids within the intima at an early stage in the development of atherosclerotic lesions.
Collapse
Affiliation(s)
- Y V Bobryshev
- Surgical Professorial Unit, St. Vincent's Hospital, Darlinghurst NSW, Australia
| | | |
Collapse
|
13
|
Affiliation(s)
- H S Kruth
- Section of Experimental Atherosclerosis, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| |
Collapse
|
14
|
Gaynor PM, Zhang WY, Salehizadeh B, Pettiford B, Kruth HS. Cholesterol accumulation in human cornea: evidence that extracellular cholesteryl ester-rich lipid particles deposit independently of foam cells. J Lipid Res 1996. [DOI: 10.1016/s0022-2275(20)37550-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
|
15
|
Gaynor PM, Zhang WY, Weiss JS, Skarlatos SI, Rodrigues MM, Kruth HS. Accumulation of HDL apolipoproteins accompanies abnormal cholesterol accumulation in Schnyder's corneal dystrophy. Arterioscler Thromb Vasc Biol 1996; 16:992-9. [PMID: 8696964 DOI: 10.1161/01.atv.16.8.992] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Schnyder's corneal dystrophy is an autosomal dominant disorder that results in clouding of the central cornea and premature development of peripheral arcus in the cornea. Previous studies showed that abnormal lipid accumulation is the basis for the corneal clouding. We examined whether apolipoproteins are involved in this disorder and characterized the lipid accumulation in the central portion of corneas removed from patients with Schnyder's dystrophy. Our findings show that cholesterol and phospholipid contents increased greater than 10-fold and 5-fold, respectively, in affected compared with normal corneas. In addition, the percentage of cholesterol that was unesterified (63% versus 50%) and the molar ratio of unesterified cholesterol to phospholipid (1.5 versus 0.5) were higher in affected compared with normal corneas. Large multilamellar vesicles and electron-dense granules (100 to 300 nm in diameter) as well as cholesterol crystals accumulated in the extracellular matrix of affected corneas. Immunohistochemical analysis showed that apolipoprotein constituents of HDL (apoA-I, apoA-II, and apoE), but not apoB, a marker of LDL, accumulated in the affected cornea. Western blot analysis confirmed the increased amounts of these HDL apolipoproteins in affected corneas and showed that the apparent molecular weights of the apolipoproteins were normal. Our findings show for the first time that HDL apolipoproteins accumulate in the corneas of patients with Schnyder's corneal dystrophy. Thus, this disorder influences the metabolism of HDL in the corneas of these patients.
Collapse
Affiliation(s)
- P M Gaynor
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda 20892-1422, USA
| | | | | | | | | | | |
Collapse
|